| Flexible thin thermal insulation material is the basic material of person thermal protection and deformable thermal insulation. Flexibility and movement without obstacle are commonly realized by two methods. The one is fiber aggregate substance that thick and bad seal. The other one is membrane multilayer combination material that affects flexible and thermal insulating performance. Aim at the latter one, we design the structure of multilayer polymer aluminum membrane and net liner interlayed to realize thin flexible and high effect thermal insulation material in this paper. Following are the particular progresses: Compare the material’s performance and analyze the thermal insulation theory and compute model of the multilayer insulation, we adopt plating aluminum composite film as reflecting screen, and still air, terylene net and Nomex fiber as spacers; Then establish thermal conductivity compute model of flexible multilayer insulation to be directed against non-vacuum; Predict the material’s thermal conductivity; Analyze the insulating performance of multilayer membrane materials which varying form structures by the compute model; Look for the best material and combinative mode to research and produce the highly effective flexible multilayer insulation in the condition of non-vacuum. Test and compare with performance of flexible multilayer thermal insulation to validate thermal transmit compute model.The flexible multilayer thermal insulation material’s indexes are conductive coefficient and thermal resistance. Experimental results indicate: first, aluminum thickness of Aluminum plating membrane affects reflectivity and thermal conductivity of combination membrane. Thickness with 300 Angstrom compared with other specifications has lower thermal conductivity. The process cost and material’s waste are lower, and craft is mature; second, although compound aluminum-plates membrane has limited influence about thermal conductivity itself, it has tremendous influence in multilayer structure. The transcalent aluminum surface is inside of compound membrane (sandwich structure). Therefore the thermal conductivity of multilayer membrane has little change; third, layer number affects the multilayer thermal insulation material performance. The best number of layer is between 25 and 30; fourth, different medium (spacer) sandwiched multilayer membrane affect the thermal insulation performance bigly. Still air as spacer material has the least thermal conductivity 0.031 lW/(m·K); fifth, reflecting screen has orientation effect. If it faces to high temperature side, the thermal conductivity will be reduced effectively; sixth, structure of net liner and compound aluminum-plates membrane is easier to assemble together. It also has stable structure. The result indicates one film with many net clothes is better than with one net cloth.Take the lamination structure of air and compound aluminum membrane as an example, we simulation compute and test its thermal insulation performance. Contrast With above two values of thermal conductivity. It indicates: though it has certain error, this computation model is simple and has good consistency. It can estimate the flexible multilayer thermal insulation material’s thermal insulation performance when know each part of material modality and thermal conductivity. At the same time, we change state of multilayer thermal insulation material. Such as join the glass fiber in the compound membrane, oxidate the surface, interlayer membrane’s thickness, different spacer, different place of compound aluminum-plates membrane, layer number of compound membrane. These all have a different extent of impact on multilayer thermal insulation material’s insulation performance. We have primary theoretically optimized these factors and get a better outcome required by item. But the method, data and result supplied by this paper will give a good reference and theoretical guidance for the designing the best thin flexible multilayer insulation material. |
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